(a) Field of Disclosure
The present disclosure of invention relates to a mask for use in a photolithography process, a manufacturing method for producing the mask and a manufacturing method for producing other devices by use of the mask.
(b) Description of Related Technology
In recent times, flat panel display devices have been differentiated and developed in various ways. Examples of flat panel display devices include various display devices such as large display area liquid crystal displays (LCD's), organic light emitting displays (OLED's), electrophoretic displays, MEMS displays (e.g., tilted micro-mirrors), and various forms of 3D displays (e.g., those using active shutters or those which otherwise project different images to the left and right eyes). Technological advances have been made in each of these respective fields. The technological advances include greater miniaturization as well increased display area.
With such technological advances, a need has emerged to form ever more minute patterns of electronic circuitry or the like in the flat panel display assemblies while at the same time enlarging the total display area of the device. In the flat panel display device industry, unlike the VLSI semiconductor industry, since there is little need to improve integrability by the forming of minute patterns throughout large display areas, it was not heretofore been required to form minute patterns which exceed the limited resolution of a legacy light exposer used in the meantime within the industry where the legacy light exposer produces light outputs over a relatively broad spectrum of wavelengths (a.k.a. herein as “complex light”) as opposed to coherent light with a specific single wavelength.
However, as flat panel display devices have been further developed, cases have come into the limelight where a need arises for forming components of a minute pattern format in a pixel or in another part of a display panel where the minute pattern has a resolution which exceeds the limited resolution capabilities of the legacy light exposer which produces light output over a relatively broad spectrum of wavelengths (a.k.a. “complex light”).
One possible answer to the emerging industry needs is to switch to the use of the more expensive, single wavelength light exposers where the latter have the capability of providing a substantially higher resolution. That is, when a light source used in the light exposer is changed to the higher resolution kind or when a Numerical Aperture value of the light exposer increases, the resolution can be improved. However, since the legacy light exposers used to manufacture display devices output complex wavelengths light having a plurality of light wavelengths, there is a cost and other problems attached to switching to use of a single wavelength light source. More specifically, such a switchover requires not only modification of the light exposer itself, but also introduction of new facilities structured to operate with the single wavelength exposer. Therefore, such a switchover requires a lot of cost and time. Further, since the changing to the single wavelength light source and the increase in the NA value can reduce a depth of focus, there is a problem in that danger of a failure will increase due to nonuniformity across the entire display device area where in the display device industry is trending towards use of larger-area substrates as opposed to the substantially smaller substrates as occurs in the shrinking die size realms of the VLSI semiconductor device industry.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.